The present invention relates to a flat film cassette. More particularly, it relates to such a flat film cassette which has a lower part, an upper part provided with an illumination opening, and means for turnably connecting said lower part with said upper part so that the cassette can be opened and closed.
Flat film cassettes of the above mentioned general type are known in the art. A known flat film cassette has the above mentioned upper and lower parts, a light protection plate which is insertable through a slot in the upper part and covers a film in the cassette in a light tight manner, light seals formed between the upper part and the lower part, a hinge turnably connected the upper part and the lower part at their one side, locking elements provided at the opposite side of the upper part and lower part. The lower part has a firm bottom with a peripheral edge for receiving the film, while the inner surface of the upper part has a frame which surrounds the illumination window, is elastic and pressed in the closed condition of the cassette against the firm bottom of the lower part.
Such a flat film cassette is disclosed for example in the German document DE-PS 3,040,819. In this cassette the edge which forms together with the bottom of the lower part a film shooting region is only insignificantly higher than the thickness of the flat film. When such cassettes are loaded in known automatic loading devices, then due to a bulging of the film toward the bottom, the film edges are lifted and extend over the edge. An automatically inserted film can project beyond the film shooting region and therefore lie in the cassette in non-accurate manner so as to cause defective shooting.